// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MEDIA_FORMATS_MP4_AAC_H_
#define MEDIA_FORMATS_MP4_AAC_H_

#include <stdint.h>

#include <vector>

#include "build/build_config.h"
#include "media/base/channel_layout.h"
#include "media/base/media_export.h"
#include "media/base/media_log.h"

namespace media {

class BitReader;

namespace mp4 {

    // This class parses the AAC information from decoder specific information
    // embedded in the esds box in an ISO BMFF file.
    // Please refer to ISO 14496 Part 3 Table 1.13 - Syntax of AudioSpecificConfig
    // for more details.
    class MEDIA_EXPORT AAC {
    public:
        AAC();
        AAC(const AAC& other);
        ~AAC();

        // Parse the AAC config from the raw binary data embedded in esds box.
        // The function will parse the data and get the ElementaryStreamDescriptor,
        // then it will parse the ElementaryStreamDescriptor to get audio stream
        // configurations.
        bool Parse(const std::vector<uint8_t>& data,
            const scoped_refptr<MediaLog>& media_log);

        // Gets the output sample rate for the AAC stream.
        // |sbr_in_mimetype| should be set to true if the SBR mode is
        // signalled in the mimetype. (ie mp4a.40.5 in the codecs parameter).
        // Returns the samples_per_second value that should used in an
        // AudioDecoderConfig.
        int GetOutputSamplesPerSecond(bool sbr_in_mimetype) const;

        // Gets the channel layout for the AAC stream.
        // |sbr_in_mimetype| should be set to true if the SBR mode is
        // signalled in the mimetype. (ie mp4a.40.5 in the codecs parameter).
        // Returns the channel_layout value that should used in an
        // AudioDecoderConfig.
        ChannelLayout GetChannelLayout(bool sbr_in_mimetype) const;

        // This function converts a raw AAC frame into an AAC frame with an ADTS
        // header. On success, the function returns true and stores the converted data
        // in the buffer. The function returns false on failure and leaves the buffer
        // unchanged.
        bool ConvertEsdsToADTS(std::vector<uint8_t>* buffer) const;

#if defined(OS_ANDROID)
        // Returns the codec specific data needed by android MediaCodec.
        std::vector<uint8_t> codec_specific_data() const
        {
            return codec_specific_data_;
        }
#endif

    private:
        bool SkipDecoderGASpecificConfig(BitReader* bit_reader) const;
        bool SkipErrorSpecificConfig() const;
        bool SkipGASpecificConfig(BitReader* bit_reader) const;

        // The following variables store the AAC specific configuration information
        // that are used to generate the ADTS header.
        uint8_t profile_;
        uint8_t frequency_index_;
        uint8_t channel_config_;

#if defined(OS_ANDROID)
        // The codec specific data needed by the android MediaCodec.
        std::vector<uint8_t> codec_specific_data_;
#endif

        // The following variables store audio configuration information that
        // can be used by Chromium. They are based on the AAC specific
        // configuration but can be overridden by extensions in elementary
        // stream descriptor.
        int frequency_;
        int extension_frequency_;
        ChannelLayout channel_layout_;
    };

} // namespace mp4

} // namespace media

#endif // MEDIA_FORMATS_MP4_AAC_H_
